More particularly, the invention relates to a connector of the type that comprises a unitary composite connector for a liquid circuit, in particular for medical applications, the connector comprising: means constituting a tubular chamber between an upstream coupling and a downstream coupling situated at opposite ends of the chamber and fixed relative to each other, said upstream coupling constituting a passage; a hollow needle which is fixed in the chamber and which is suitable for causing the upstream coupling to communicate with the downstream coupling; and a plug suitable for being passed through by the needle, the plug being mounted in the passage of the downstream coupling so as to be capable of sliding between a downstream stable closure position where the plug closes said passage and where the needle does not pass through the plug, and an upstream position where said needle does pass through the plug and towards which the plug can be pushed by a member inserted in said passage from outside said connector, and means situated in the chamber resiliently urging the plug towards its stable closure position, the material of the plug being such that the plug retrieves its closure properties when the needle is not passing through it.
Such a unitary composite connector is particularly useful in medical applications, for example when injecting a liquid into the body of a patient, and various embodiments have been described, in particular in Documents EP 0 309 771 and U.S. Pat. No. 4,998,927.
Those publications demonstrate that it is difficult to obtain a unitary composite connector of acceptable manufacturing costs that provide reliable and effective coupling and that is free from any danger of contamination.
An object of the invention is to provide a novel unitary composite connector of the above-described type, suitable for providing a coupling that is reliable and effective, that is of acceptable manufacturing cost, particularly if the connector is to be discarded after use, and that does not present any risk of contaminating the liquid circuit, in particular in the region of its downstream coupling.